The electronic structure of heme proteins is being investigated using a combined theoretical and experimental approach, that includes extended Huckel molecular orbital calculations and various electronic spectroscopic measurements. BIBLIOGRAPHIC REFERENCES: Hanson, L. K., Sligar, S. G. and Gunsalus, I. C.: Electronic structure of cytochrome P450. Croatia Chemica Acta 2: 237-250, 1977. Hofrichter, J. and Eaton, W. A.: Linear dichroism of biological chromophores, Annual Review of Biophysics and Bioengineering 5: 511-560, 1976. In press.